Two-cycle internal-combustion engine



- -July 29 1924.

L. L. SCOTT TWO-CYCLE INTERNAL COMBUSTION ENGINE llllll III: Il!

Filed July 31 1922 p Patented July 29, 1924.

UNITED STATES LELAND L. SCOTT, 0F SAVANNAH, MISSOURI.

TWO-CYCLE INTERNAL-COMBUSTION ENGINE.

Application mee my 31, 1922. serial No. 578,669.,

To all whom t may concern:

. Be it known that I, LELAND L. Soo'rr, a citizen of the United States,residing at Savannah, in the county of Andrew and State of Missouri,have invented a certain new and useful Improvement in Two-CycleInternal-Combustion Engines. of which the following is a completespecification.

This invention relates to two-cycle internal combustion engines and hasfor one of its objects toproduce a stationary inside head secured to oneend of the cylinder and adapted to work in combination `with an invertedcup-shaped piston, machined inside and outside.

Another object is to produce an engine of i the general charactermentioned equipped with a new and novel by-pass arrangement whereby aconstant and steady suction'shall be maintained on the up stroke of thepiston, as well as a constant and steady compression of the mixture inthe by-pass chamber on the down stroke of the piston, consequentlyentirely obviating apause period pending the operation of the piston.

A further object is to provide a ported piston and by-pass structure/ofsuch character that the motor 'can be readily and easily adapted tofunction with an inlet Avalve of any suitable automatic or mechanicalconstruction and in communication with the by-pass chamber of theengine.

Another object is to obviate the present sluggishness of the ordinarytype of twocycle engine, d-ue to the fact that ordinarily the mixture iscompressed in the crank case, orv between the piston and a stationaryhead, and then at the proper time is allowed to escape through a more orless extended bypass chamber into the cylinder. I have found that thesluggishness of an engine, constructed as just described, is due to amore or less condensation of the combustible mixture during` its passagethrough the bypass, and in order to overcome this diiticulty I- havedesigned the engine of this application, in which the combustiblemixture is compressed in the by-pass chamber itself, and permitted toescape directly into the cylinder.

The objects of the Ainvention are accomplished by providing the by-passchamber with a long vertical port and forming the piston with a pair ofsimilar spaced ports so arranged that one of' the piston ports isconstantly in register with the by-pass port .asiwill be explained indetail, hereinbelow'.

With the objects named in view the invention consists in certain noveland useful features of construction and organization of parts ashereinafter described and claimed; and in order that it may be fullyunderstood, reference is to be had to the accom- The cylinder block 1 isformed with anextension 4 projecting into the crank-case and forming acontinuation of the cylinder,

and secured to said extension isa fixed Ainternal cylinder provided withthe customary piston rings, and head 5, formed at its lower end with aflange 6 and Asecured in position to the lower end of the part 4 asclearly shown in Figure 1. The lixed cylinder head 5 is, of course, ofcylindrical form and is formed at its lower `end with a pair ofoppositely disposed vertical slots 6 for the reception of areciprocating part hereinafter mentioned. A

Mounted in the cylinder for reciprocation therein is a piston -7provided with suitable external piston rings and formed with an externalskirt portion 8, said skirt portion being secured at its lower end toawrist pin 9 secured to the connecting rod 10, as customary. At its upperend the piston head may or an inlet valve driven mechanically from thecrankshaft may be employed if desirable,

said valve to open directly into the by-passV chamber, hereinafterreferred to.

n the opposite side of the cylinder a large rectangular port 13a isformed, which is 1n communication with a by-pass chamber 14 closed by aremovable cap 15.

' opposite side, is formed with a pair of similar ports 18 and 19 sospaced vertically apart that one of these ports will be constantly inregister with the long port 13 in the cylinder wall regardless of theposition of the piston.

Theoperation of the engine is`substan- W tially as follows z-Upon theupstroke of the -will be drawn into the engine.

iston, a vacuum will be created between the ottom of the piston and thefixed head 5 and immediately the port 17 registers with the intake port13, the combustible mixture As one or the other of the ports 18 and 19constantly register with the oy-pass chamber, upon the commencement ofthe down stroke, this combustible mixture will be constantly and evenl;compressed in the bypass chamber 14 t rough the long vertica port 13".

Immediately the upper end of the long port 13u is uncovered by the topof the piston, the combustible mixture will rush directl into the firingchamber as will be readily understood.

It will be apparent from the above that by means of the double portarrangement in the piston and the long port in the by-pass chamber,there is a continual and steady increase in the compression on the downstroke of the piston of the combustible mixture in the by-pass chamber,from which it is permitted torush directly into the cylinder. I havefound by experiment that when the combustible mixture is compressedbetween the underside of the piston and the iixed head and then at theproper time permitted to rush around through a b -pass and into thecylinder, there is aresulting sluggishness of o eration due to the factthat there is a con ensation of the mixture pending its journey throughthe by-pass. With an engine embodying the invention, however, thisdraw-back is obviated.

From the above description it will be apparent that I have produced a'device of the character described, which possesses all of the featuresof advantage set forth as desirable, andwhile I have described andclaimed the preferred embodiment of the same, I reserve the right tomake all changes properly falling wlthin the spirit and scope of theappended claim.

I claim In a two-cycle internal combustion engine, a cylinder having anelongated bore, an internal cylinder head bolted to the extremity ofsaid cylinder and closing the end thereof and being provided with aseries of piston rings, a piston for reciprocation in said cylinder andhaving its internal face in frictional contact with the rings of saidinternal head, a combustible mixture supply and an exhaust port in saidcylinder, a by-pass chamber having a single port with its lower edge inhorizontal alinement with the top of the internal head, a pair of portsin said piston; said by-pass and piston ports being so arranged thatthere shall be an uninterrupted compression of the combustible mixturein the by-pass chamber on the back stroke of the piston, one ofsaidpiston ports passing beyond the rings of the internal head on theback stroke of the piston, and a supply port in said piston adapted forre istration at times with said cylinder supp y .port and on the backstroke of the piston Ipasing beyond the rings of the internal signature.

LELAND L. SCOTT.

